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Assembly Source File | 1989-04-22 | 38.2 KB | 1,105 lines

page 58,132 ;---------------------------------------------------------------- ; PCMAP 2.0 - Jeff Hasty (CompuServe 71121,2352) - April, 1989 ; Documentation in PCMAP2.DOC ;---------------------------------------------------------------- ;---------------------------------------------------------------- ; EQUATES ;---------------------------------------------------------------- MAX_BLK EQU 23 ;Number of spaces in table INT9_BUSY EQU 1 ;Mask for BUSY byte INT10_BUSY EQU 2 ;Mask for BUSY byte SHIFT_MASK EQU 8 ;Mask for hot key (8=Alt) HOTKEY EQU 19H ;Scan code (19h=P) CR EQU 0DH ; ASCII carriage return LF EQU 0AH ; ASCII line feed TAB EQU 09h ; ASCII tab BLANK EQU 20h ; ASCII space character ;---------------------------------------------------------------- ; START - entry point for command-line mode ;---------------------------------------------------------------- _TEXT SEGMENT PARA PUBLIC 'CODE' ;set up for .COM file ASSUME CS:_TEXT,DS:_TEXT ORG 100H START: JMP RES ;jump to installation routines ;---------------------------------------------------------------- ; RESIDENT DATA AREA ;---------------------------------------------------------------- ID DB "PCMAP 2.0 - Jeff Hasty (CompuServe 71121,2352)" DB " - April, 1989",1Ah HEADING_MSG DB CR,LF DB "Segment Size Program" DB CR,LF DB "Address Owner (para) Type Name" DB CR,LF DB "0000",18 DUP(' '),0 BLOCK1_MSG DB 10 DUP (' '),"DOS + Drivers",CR,LF,0 CR_LF_MSG DB CR,LF,0 COM_MSG DB "COMMAND.COM" PSP_MSG DB "PSP" ENV_MSG DB "ENV" UNK_MSG DB "(Unknown)" FREE_MSG DB "(Free)" SPACE3_MSG DB " " SPACE_MSG DB 7 DUP(' '),0 TABLE_FULL_MSG DB "Out of space ",0 PROGRAM_ID DB "PCMAP 2.0",0 HIT_ANY_KEY DB " - Hit any key to return...",0 DISABLE DB 0 ;flag to disable if cannot uninstall TSR_MODE DB 1 ;=0 if command line mode VER3 DB 0 ;=1 if Version >= 3.0 LAST_BLOCK DB 0 ;=1 if last MCB TABLE_FULL DB 0 ;=1 if table full CURSOR_POS DW 0 ;to store cursor position BIOS_SEG DW 40H ;address of bios data area DIFF DW 0 ;# of chars on a line > 80 N_BLK DB 0 ;Count table entries OUR_SS DW 0 ; used for stack swap OUR_SP DW 0 THEIR_SS DW 0 THEIR_SP DW 0 RETADDR DW 0 ADDR_INT9H DD 0 ;to save original vectors ADDR_INT10H DD 0 BUSY DB 0 ;to store status of int 9 and int 10h ;---------------------------------------------------------------------- ; INT9H - entry point for memory-resident mode. ; pressing any key causes entry here. ;---------------------------------------------------------------------- INT9H PROC FAR STI ;interrupts on PUSH AX ;save working register CMP CS:DISABLE,-1 ;if disabled, do nothing JE NOT_US IN AL,60H ;get key from keyboard port CMP AL,HOTKEY ;is it our hotkey? JNE NOT_US ;if not, exit MOV AH,2 ;otherwise INT 16H ;get shift status AND AL,0FH CMP AL,SHIFT_MASK ;test the shift status JNE NOT_US ;if not shift combo, exit IN AL,61H ;These instructions reset MOV AH,AL ; the keyboard. OR AL,80H OUT 61H,AL MOV AL,AH JMP SHORT $+2 ;I/O delay for fast AT's OUT 61H,AL CLI ;Disable interrupts and MOV AL,20H ;reset the int controller OUT 20H,AL STI CMP CS:BUSY,0 ;recursion protection JNE WE_ARE_BUSY ;dont allow re-entrancy OR CS:BUSY,INT9_BUSY ;set flag for protection CALL ADJUST_FOR_VIDEO_MODE JC CANT_POP_UP ;exit if inappropriate mode CALL MAIN ;call our program CANT_POP_UP: CLI ;disable kbd momentarily AND CS:BUSY,NOT(INT9_BUSY) ;reset protection WE_ARE_BUSY: POP AX ;restore working register STI IRET ;return to foreground NOT_US: POP AX ;restore working register CLI ;interrupts off JMP CS:ADDR_INT9H ;jump to original int 9 INT9H ENDP ;----------------------------------------------------------------- ; ADJUST_FOR_VIDEO_MODE ; check for text modes and set offset for lines > than 80 characters ; in length. sets carry flag if inappropriate mode for pop-up. ;----------------------------------------------------------------- ADJUST_FOR_VIDEO_MODE PROC NEAR PUSH BX ;save register MOV AH,15 ;get present mode INT 10H CMP AH,80 JB BAD_MODE ;less than 80 chars per line MOV CS:BYTE PTR DIFF,AH ;calc the # of chars > 80 SUB CS:BYTE PTR DIFF,80 ;on the line & save in diff CMP AL,7 ;7 is mono, good mode JNE TRY_COLOR MODE_OK: CLC ;clear carry flag POP BX ;restore register RET TRY_COLOR: CMP AL,3 ;3 is color 80x25, JBE MODE_OK ; 2 is B&W 80x25 BAD_MODE: STC ;not good mode, set carry flag POP BX ;restore register RET ADJUST_FOR_VIDEO_MODE ENDP ;----------------------------------------------------------------- ; MAIN - main routine called by pressing hot key ;----------------------------------------------------------------- MAIN PROC NEAR CLD ;strings forward CALL SWAPIN ;new stack MOV AX,CS ;our data segment is MOV DS,AX ; same as CS CALL GETPOS ;save cursor position CALL CURSOR_HOME ;cursor to 0,0 CALL SAVE_SCREEN ;save screen CALL CLEAR_SCREEN ;clear screen CALL PROGRAM ;construct & display memory map MOV TABLE_FULL,0 ;reset flag CALL RESTORE_SCREEN ;put screen back CALL RESTORE_CURSOR ;cursor to original position CALL SWAPOUT ;put stack back RET ;that's all MAIN ENDP ;----------------------------------------------------------------- ; SWAPIN, SWAPOUT - stack routines ;----------------------------------------------------------------- SWAPIN PROC NEAR POP CS:RETADDR ;save callers address MOV CS:THEIR_SS,SS ;save their stack MOV CS:THEIR_SP,SP MOV SS,CS:OUR_SS ;switch to our stack MOV SP,CS:OUR_SP PUSH AX ;save all registers PUSH BX PUSH CX PUSH DX PUSH SI PUSH DI PUSH ES PUSH DS PUSH BP JMP CS:RETADDR ;return to caller SWAPIN ENDP ;----------------------------------------------------------------- SWAPOUT PROC NEAR POP CS:RETADDR ;save callers address POP BP ;restore all registers POP DS POP ES POP DI POP SI POP DX POP CX POP BX POP AX MOV SS,CS:THEIR_SS ;restore callers stack MOV SP,CS:THEIR_SP JMP CS:RETADDR ;return to caller SWAPOUT ENDP ;----------------------------------------------------------------- ; GETPOS, CURSOR_HOME, RESTORE_CURSOR, SETPOS - cursor routines ;----------------------------------------------------------------- GETPOS PROC NEAR MOV AH,3 ;get cursor position XOR BH,BH ;active page INT 10H ;get cursor position in dx MOV CURSOR_POS,DX ; and save RET GETPOS ENDP ;---------------------------------------------------------------------- CURSOR_HOME PROC NEAR XOR DX,DX ;position 0,0 CALL SETPOS ;set cursor position RET CURSOR_HOME ENDP ;---------------------------------------------------------------------- RESTORE_CURSOR PROC NEAR MOV DX,CURSOR_POS ;saved position CALL SETPOS ;set RET RESTORE_CURSOR ENDP ;---------------------------------------------------------------------- SETPOS PROC NEAR MOV AH,2 ;set cursor position XOR BH,BH ;active page INT 10H ;set cursor position to dx RET SETPOS ENDP ;----------------------------------------------------------------- ; SAVE_SCREEN, CLEAR_SCREEN, RESTORE_SCREEN - screen routines ;----------------------------------------------------------------- SAVE_SCREEN PROC NEAR PUSH DS ;save data segment XOR AX,AX MOV BX,AX CALL CALC_SCRN_ADDR ;address of (0,0) MOV SI,OFFSET SCREEN ;buffer is past end of table PUSH DS ;exchange PUSH ES ;ds and es POP DS POP ES XCHG DI,SI ;exchange source,destination MOV BX,25 ;save 25 lines SAVE_NEXT_LINE: MOV CX,80 ;save 80 words per line REP MOVSW ;save line ADD SI,CS:DIFF ;add extra characters and ADD SI,CS:DIFF ; attributes to SI DEC BX ;decrement line counter JNZ SAVE_NEXT_LINE POP DS ;restore data segment RET SAVE_SCREEN ENDP ;----------------------------------------------------------------- CLEAR_SCREEN PROC NEAR XOR AX,AX MOV BX,AX CALL CALC_SCRN_ADDR ;address of (0,0) MOV AX,0720H ;space with normal attribute MOV BX,25 ;clear 25 lines CLEAR_NEXT_LINE: MOV CX,80 ;clear 80 words per line REP STOSW ;clear line ADD DI,CS:DIFF ;add extra characters and ADD DI,CS:DIFF ; attributes to SI DEC BX ;decrement line counter JNZ CLEAR_NEXT_LINE RET CLEAR_SCREEN ENDP ;----------------------------------------------------------------- RESTORE_SCREEN PROC NEAR XOR AX,AX MOV BX,AX CALL CALC_SCRN_ADDR ;address of (0,0) MOV SI,OFFSET SCREEN ;buffer past end of table MOV BX,25 ;restore 25 lines RESTORE_NEXT_LINE: MOV CX,80 ;restore 80 words per line REP MOVSW ;restore line ADD DI,CS:DIFF ;add extra characters and ADD DI,CS:DIFF ; attributes to SI DEC BX ;decrement line counter JNZ RESTORE_NEXT_LINE ;25 lines RET RESTORE_SCREEN ENDP ;------------------------------------------------------------------ ; CALC_SCRN_ADDR ; ax = row bx= col, returns es:di pointing to the screen address ;------------------------------------------------------------------ CALC_SCRN_ADDR PROC NEAR PUSH CX ;save CX PUSH DX ;save DX (mul destroys DX) PUSH AX ;save AX for later MOV ES,CS:BIOS_SEG ;bios data segment into ES MOV AX,0B800H ;scrn seg = b800h (assume color) CMP ES:BYTE PTR[49H],7 ;40:49 = 7? JNZ COLOR ; no, color MOV AH,0B0H ; yes, mono, scrn seg = b000h COLOR: MOV ES,AX ;scrn seg into es POP CX ;get row MOV AX,160 ;160 bytes to a row of text ADD AX,CS:DIFF ;# characters > 80 ADD AX,CS:DIFF ;# of attribute bytes > 80 MUL CX ;row * 160 + diff*2 ADD AX,BX ;+col ADD AX,BX ;row*160 + col*2 MOV DI,AX ;es:di points to right address POP DX ;restore registers POP CX RET ;that's all CALC_SCRN_ADDR ENDP ;---------------------------------------------------------------------- ; PROGRAM ; Find the first MCB by scanning through memory. All MCBs have the ; character "M" as the first byte (except the last MCB, which has "Z" ; as the first byte. The second and third bytes give the segment ; address of the PSP block of the "owner" (the program which allocated ; the memory block). The fourth and fifth bytes give the length of ; the block in paragraphs. The first block is COMMAND.COM, which ; follows such things as the operating system and device drivers. ; On entry, AX=Memory block Address, BX=ES, CX=Owner. ; On exit, ES points to the first valid MCB. ;---------------------------------------------------------------------- PROGRAM PROC NEAR XOR BX,BX ;Zero BX SRCH_MEM: MOV ES,BX ;Point ES to next paragraph CMP BYTE PTR ES:[0],'M' ;Is this a MCB? JE CHECK_MCB ; might be CRAWL: INC BX ;Point to next paragraph JMP SRCH_MEM ; continue search CHECK_MCB: MOV AX,BX ;Point AX to next paragraph INC AX ; (possible 1st memory block) MOV CX,WORD PTR ES:[1] ;If first block is COMMAND.COM, CMP AX,CX ; it will "own" itself JNE CRAWL ;If not, continue search FOUND_FIRST: MOV DI,OFFSET TABLE ;Table offset in DI ; Add an entry to the table. ; If the owner=0, then this block is unallocated (free). ; AX=Mem Address, BX=ES=MCB address, CX=Owner. ; DI points to 1st empty spot in table. CREATE_ENTRY: INC N_BLK ;Adding new entry MOV WORD PTR [DI],AX ;Put block addr in table MOV WORD PTR [DI+2],CX ;Put owner in table MOV SI,WORD PTR ES:[3] ;Put block length in MOV WORD PTR [DI+4],SI ; table via SI MOV SI,OFFSET SPACE3_MSG ;Blanks in type column MOV CX,3 ;String length ADD DI,6 ;Address in table CALL COPY_NAME ;Move blanks to table MOV CX,WORD PTR ES:[1] ;Owner segment back into CX OR CX,CX ;If owner <> 0, determine JNZ HAVE_OWNER ; type and find owner name. MOV CX,6 ; Else set string length, MOV SI,OFFSET FREE_MSG ; point SI to "(Free)", CALL COPY_NAME ; and copy to table JMP FIND_NEXT ;Next memory block ; Is this block a PSP (program) block? HAVE_OWNER: CMP AX,CX ;Is mem = owner? JNE FIND_NAME ;No, not PSP block, jump SUB DI,4 ;Yes, set table destination MOV SI,OFFSET PSP_MSG ;Point SI to "PSP" string MOV CX,3 ;String length CALL COPY_NAME ;Move string to table ; If this is first block, it is COMMAND.COM. FIND_NAME: CMP N_BLK,1 ;If not first block JNE FIND_ENV ; look for environment MOV SI,OFFSET COM_MSG ;Point to "COMMAND.COM" string MOV CX,11 ;String length CALL COPY_NAME ;Put name in table JMP FIND_NEXT ;Next memory block ; Word at offset 2Ch into the owner's PSP block contains the ; environment segment address. FIND_ENV: MOV CX,WORD PTR ES:[1] ;Owner segment into CX MOV ES,CX ; and ES CMP CX,WORD PTR DS:[TABLE] ;Is owner COMMAND.COM? JNE NOT_COMMAND ;No, jump CMP N_BLK,2 ;2nd block? JNE NOT_ENV ;No, jump MOV SI,OFFSET ENV_MSG ;Yes, is system environment MOV CX,3 ;String length SUB DI,4 ;Restore destination CALL COPY_NAME ;Move string to table NOT_ENV: MOV SI,OFFSET COM_MSG ;"COMMAND.COM" to table MOV CX,11 CALL COPY_NAME JMP FIND_NEXT ;Next memory block ; Is this block an ENV (environment) block? NOT_COMMAND: MOV SI,WORD PTR ES:[2Ch] ;Get owner's env segment CMP AX,SI ;Is this block owner's env? JNZ EXTR_NAME ;No, jump PUSH SI ;Save SI (env segment) MOV SI,OFFSET ENV_MSG ;Point SI to "ENV" string MOV CX,3 ;String length SUB DI,4 ;Restore destination CALL COPY_NAME ;Move string to table POP SI ;Restore SI ; Get name from environment (if DOS 3.x or later) EXTR_NAME: CMP VER3,0 ;If not 3.x JE NO_ENV ; skip this section ; Is env still allocated to owner of current block? MOV CX,ES ;Owner segment to CX DEC SI ;Point to env MCB PUSH SI ;and put in DS POP DS CMP CX,WORD PTR DS:[1] ;Compare owners JNZ NO_ENV ;Not our property ; The environment block terminates with two zero bytes. In DOS 3.0 ; and later, the double zero is followed by a string count (two bytes) ; and the fully qualified file name of the owner program, terminated ; by a zero byte. ; Point DS:SI to the environment and scan for the double zero entry. INC SI ;Point SI to environment PUSH SI ; and put in DS POP DS XOR SI,SI ;DS:SI = ENV:0 INC SI SCAN_ENV: DEC SI ;Backup one byte, SI=SI-1 LODSW ;Look at word, SI=SI+2 OR AX,AX ;If not double 0 byte JNZ SCAN_ENV ;Continue to look ; Find the end of the program pathname. LODSW ;Skip a word (string count) MOV BP,SI ;SI points to 1st char DEC BP ;BP points before 1st char SCAN_PATH: LODSB ;Read char at SI OR AL,AL ;If 0, end of string JNZ SCAN_PATH ; else continue reading ; SI points past the terminating 0. Scan backwards for the \. DEC SI ;Point SI and CX to the MOV CX,SI ; zero byte past last char SCAN_NAME: DEC SI ;Point to char CMP SI,BP ;Is it before 1st char? JE STRING_START CMP BYTE PTR [SI],'\' ;It is backslash? JNE SCAN_NAME ; no, continue STRING_START: INC SI ;Point to start of string SUB CX,SI ;Length of string CALL COPY_NAME ;Transfer to table JMP FIND_NEXT ;Next memory block NO_ENV: PUSH CS ;Restore DS POP DS MOV CX,9 ;Number of chars MOV SI,OFFSET UNK_MSG ;Point to "Unknown" string CALL COPY_NAME ;Transfer to table ; Point ES to next MCB and continue search. Stop at top of memory. FIND_NEXT: PUSH CS ;Restore DS POP DS CMP LAST_BLOCK,1 ;was this last block? JE NO_MORE ; yes, done CMP N_BLK,MAX_BLK ;out of space? JE OUT_OF_SPACE ; yes, jump MOV ES,BX ;ES to current MCB ADD BX,WORD PTR ES:[3] ;BX to next MCB INC BX MOV ES,BX ;ES too CMP BYTE PTR ES:[0],'Z' ;is this last block? JNE MORE_BLOCKS ; no, jump INC LAST_BLOCK ; yes, set flag MORE_BLOCKS: MOV AX,BX ;Put address of block INC AX ; in AX MOV DI,OFFSET TABLE ;Find MOV CL,N_BLK ; address XOR CH,CH ; of ADDEM: ; next ADD DI,23 ; table LOOP ADDEM ; entry MOV CX,WORD PTR ES:[1] ;Block length in CX JMP CREATE_ENTRY ;Continue with next entry OUT_OF_SPACE: INC TABLE_FULL ;set flag for out of space msg ; Display the resulting table on the screen. NO_MORE: MOV SI,OFFSET HEADING_MSG ;Display the heading CALL DISPLAY_STRING MOV SI,OFFSET TABLE ;Table location CALL PRINT_WORD ;1st table entry is address ;of COMMAND.COM = size of ;initial memory block MOV SI,OFFSET BLOCK1_MSG ;Display 1st block description CALL DISPLAY_STRING MOV SI,OFFSET TABLE ;Table location MOV CL,N_BLK ;Number of entries XOR CH,CH ; as a word PRINT_TABLE: CALL PRINT_WORD ;Print address CALL PRINT_WORD ; and owner CALL PRINT_WORD ; and size CALL DISPLAY_STRING ;Print type PUSH SI ;save SI MOV SI,OFFSET SPACE_MSG ;Space over CALL DISPLAY_STRING POP SI ;restore SI ADD SI,4 ;Point to owner name CALL DISPLAY_STRING ;and print PUSH SI ;save SI MOV SI,OFFSET CR_LF_MSG ;Newline CALL DISPLAY_STRING POP SI ;restore SI ADD SI,13 ;point to start of next entry ;pause if CTRL-S pressed MOV AH,1 ;keystroke waiting? INT 16H JZ LOOP_NOW ;no, proceed MOV AH,0 ;get keystroke scan code INT 16H CMP AH,31 ;is it S? JNE LOOP_NOW ;no, proceed MOV AH,2 ;get shift status INT 16H AND AL,0FH ;mask off status of toggles CMP AL,4 ;CTRL depressed? JNE LOOP_NOW ;no, proceed MOV AH,0 ;yes, wait for next keystroke INT 16H LOOP_NOW: LOOP PRINT_TABLE ;print next entry CMP TABLE_FULL,0 ;is table full? JE DONE ; no, jump MOV SI,OFFSET TABLE_FULL_MSG ; yes, print out of space msg CALL DISPLAY_STRING DONE: MOV N_BLK,0 ;reset counter MOV LAST_BLOCK,0 ;and flag MOV SI,OFFSET PROGRAM_ID ;print progam ID CALL DISPLAY_STRING CMP TSR_MODE,1 ;TSR mode? JNE PROGRAM_EXIT ; no, exit now MOV SI,OFFSET HIT_ANY_KEY ; yes, print message CALL DISPLAY_STRING XOR AH,AH ;wait for keystroke INT 16H PROGRAM_EXIT: RET PROGRAM ENDP ;---------------------------------------------------------------------- ; COPY_NAME ; Move string at DS:SI to CS:DI, string length in CX, add 0 at end ;---------------------------------------------------------------------- COPY_NAME PROC NEAR PUSH AX ;Save AX PUSH ES ;Save ES PUSH CS ;Point ES to POP ES ; this segment REP MOVSB ;Put name in table MOV AL,0 ;string terminator STOSB ;Store it in table POP ES ;Restore ES POP AX ;Restore AX RET COPY_NAME ENDP ;---------------------------------------------------------------------- ; PRINT_WORD - Print hex value of word at DS:SI, followed by spaces ;---------------------------------------------------------------------- PRINT_WORD PROC NEAR LODSW ;Get value CALL HEX4 ;Write 4 digits PUSH SI ;save SI MOV SI,OFFSET SPACE_MSG ;space over CALL DISPLAY_STRING POP SI ;restore SI RET PRINT_WORD ENDP ;---------------------------------------------------------------------- ; HEX4 - Write AX as 4 hex digits to console ; HEX2 - Write AL as 2 hex digits to console ;----------------------------------------------------------------------------- HEX4 PROC NEAR PUSH AX ;Save register MOV AL,AH ;Show high digits first CALL HEX2 ;Display AL POP AX ;Restore low digits in AL HEX2 PROC NEAR ;Display AL PUSH AX ;Save register PUSH CX ;Save CX during shift MOV CL,4 SHR AL,CL ;Get high 4 bits POP CX ;Restore CX CALL H2C ;Display upper AL digit POP AX ;Restore lower AND AL,0FH ;Mask and display H2C: ADD AL,90H ;Convert AL to ASCII DAA ADC AL,40H DAA MOV AH,0EH ;Display character XOR BH,BH INT 10H RET HEX2 ENDP HEX4 ENDP ;------------------------------------------------------------------ ; DISPLAY_STRING - displays string at ds:si ;------------------------------------------------------------------ DISPLAY_STRING PROC NEAR PUSH SI ;save registers PUSH AX PUSH BX NEXT_CHAR: LODSB ;get character OR AL,AL ;is it zero? JZ LAST_CHAR ; yes, done MOV AH,0EH ;print character XOR BH,BH ;page 0 INT 10H JMP NEXT_CHAR LAST_CHAR: POP BX ;restore registers POP AX POP SI RET DISPLAY_STRING ENDP ;---------------------------------------------------------------------- ; INT10H ; this routine sets bit to prevent popping up while int 10h is active ;---------------------------------------------------------------------- INT10H PROC FAR OR CS:BUSY,INT10_BUSY ;set bit PUSHF ;push flags to simulate INT CALL CS:ADDR_INT10H ;call original int 10h PUSHF ;save flags AND CS:BUSY,NOT(INT10_BUSY) ;clear bit POPF ;restore flags RET 2 ;return from int 10h INT10H ENDP ;---------------------------------------------------------------------- ; end of resident code, and start of memory used for table, screen save ; buffer, and stack. each table entry has structure: ; address dw ? ; owner dw ? ; size dw ? ; type db "XXX",0 ; name db "FILENAME.EXT",0 ; (total 23 bytes per entry) ;---------------------------------------------------------------------- TABLE DB (MAX_BLK*23) DUP (20H) ;reserve space for table SCREEN LABEL BYTE ;marks start of memory used ;---------------------------------------------------------------------- ; TRANSIENT DATA AREA ;---------------------------------------------------------------------- INSTALLED DB "PCMAP installed" DB CR,LF,"Hotkey is Alt-P",CR,LF,"$" UNINSTALLED DB "PCMAP Uninstalled",CR,LF,"$" DISABLED DB CR,LF,"PCMAP is disabled",CR,LF,"$" ENABLED DB CR,LF,"PCMAP is re-enabled",CR,LF,"$" INSTALLED_SEGMENT DW 0 ;addr of resident copy START_OFFSET DW 0 ;used by search_mem START_SEGMENT DW 0 END_OFFSET DW 0 END_SEGMENT DW 0 SEARCH_PARAS DW 0 SEARCH_BYTES DW 0 ;----------------------------------------------------------------- ; RES - code relating to residency ;----------------------------------------------------------------- RES PROC NEAR CLD ;strings forward CALL CHECK_VER ;See if DOS vers >=3.0 MOV BX,80H ;ES:BX=command tail CALL ARGV ;Get 1st argument CMP AX,2 ;If argument length<>2, JNE NO_RES ; proceed with program MOV AX,ES:[BX] ;Get argument (bytes reversed) AND AH,0DFH ;Convert to upper case CMP AX,'R/' ;If not '/R', JNE NO_RES ; proceed with program, CALL PROGRAM_ALREADY_IN ; else see if already installed JNZ NOT_IN ;if not in, it's ok to install CALL UNINSTALL ;else, try to uninstall MOV AX,4C00H ;terminate with error code=0 INT 21H NO_RES: DEC TSR_MODE ;command line mode CALL PROGRAM ;Display memory map MOV AX,4C00H ;terminate, assume error code=0 CMP TABLE_FULL,1 ;out of space error? JNE RES_EXIT ; no, jump MOV AL,01 ; yes, error code=1 RES_EXIT: INT 21H NOT_IN: MOV OUR_SS,CS ;set stack seg MOV OUR_SP,OFFSET TABLE+(MAX_BLK*23)+4000+256 ;and pointer ;(256 byte stack follows table and scrn buffer) CALL INSTALL MOV DX,OFFSET INSTALLED ;confirm installation MOV AH,9 INT 21H ;program, table, scrn buf, stack, round up, cnvrt to paras MOV DX,(OFFSET TABLE-OFFSET _TEXT+(MAX_BLK*23)+4000+256+15) SHR 4 MOV AX,3100H ;stay resident, error code=0 INT 21H RES ENDP ;-------------------------------------------------------------------- ; CHECK_VER - check DOS version ;-------------------------------------------------------------------- CHECK_VER PROC NEAR MOV AH,30H ;Check DOS version INT 21H ; Thru DOS CMP AL,3 ;If not 3.x or later JB NOT_3 ; don't turn on flag INC VER3 ; else, indicate NOT_3: RET CHECK_VER ENDP ;-------------------------------------------------------------------- ; ARGV ; Call with: ES:BX = command line address ; (implicit: ES=PSP segment, BX=80h) ; ; Returns: ES:BX = argument address (first argument) ; AX = argument length ; (0=argument not found) ; Other registers preserved. ;-------------------------------------------------------------------- ARGV PROC NEAR ; get address & length of ; command tail argument PUSH CX ; save original CX and DI PUSH DI ARGV1: ARGV2: INC BX ; point to next character CMP BYTE PTR ES:[BX],CR JE ARGV7 ; exit if carriage return CMP BYTE PTR ES:[BX],BLANK JE ARGV1 ; outside argument if ASCII blank CMP BYTE PTR ES:[BX],TAB JE ARGV1 ; outside argument if ASCII tab ARGV4: ; found desired argument, now ; determine its length... MOV AX,BX ; save param. starting address ARGV5: INC BX ; point to next character CMP BYTE PTR ES:[BX],CR JE ARGV6 ; found end if carriage return CMP BYTE PTR ES:[BX],BLANK JE ARGV6 ; found end if ASCII blank CMP BYTE PTR ES:[BX],TAB JNE ARGV5 ; found end if ASCII tab ARGV6: XCHG BX,AX ; set ES:BX = argument address SUB AX,BX ; and AX = argument length JMP ARGVX ; return to caller ARGV7: XOR AX,AX ; set AX = 0, argument not found JMP ARGVX ; return to caller ARGVX: ; common exit point POP DI ; restore original CX and DI POP CX RET ; return to caller ARGV ENDP ;------------------------------------------------------------------ ; PROGRAM_ALREADY_IN - determine if program is already installed. ; returns zero flag = 1 if installed. ;------------------------------------------------------------------ PROGRAM_ALREADY_IN PROC NEAR NOT WORD PTR START ;mark this program as active MOV START_SEGMENT,60H ;start after dos MOV START_OFFSET,0 ; MOV END_SEGMENT,CS ;stop looking before you MOV END_OFFSET,0 ; get to this program MOV SI,OFFSET START ;start compare at modified byte ; (a previously installed copy ; will also have modified byte) MOV CX,25 ;compare 25 bytes CALL SEARCH_MEM ;search PUSHF ;save zr flag MOV AX,START_SEGMENT ;get address of find MOV INSTALLED_SEGMENT,AX ;save in installed address MOV AX,START_OFFSET MOV CL,4 SHR AX,CL SUB AX,10H ;adjust for psp ADD INSTALLED_SEGMENT,AX POPF ;restore flgs from search RET PROGRAM_ALREADY_IN ENDP ;----------------------------------------------------------------- ; SEARCH_MEM ; DS:SI = search string CX = string_size ; search for match of string beginning at START_SEGMENT:START_OFFSET, ; and ending at END_SEGMENT:END_OFFSET. if found, zero flag set, ; START_SEGMENT:START_OFFSET points to find. ;----------------------------------------------------------------- SEARCH_MEM PROC NEAR MOV DI,CX ;save string size CALL END_MINUS_START ;calculate search length LOOK_AGAIN: CMP SEARCH_PARAS,1000H ;more than or equal 64k? JAE MORE_THAN_ENOUGH ;if so, search 64k MOV AX,SEARCH_PARAS ;otherwise, get what's left MOV CL,4 ; SHL AX,CL ;segs*16 = bytes to search ADD AX,SEARCH_BYTES ;add in the last few bytes JMP SHORT LOOK ;and go look MORE_THAN_ENOUGH: MOV AX,0FFFFh ;64K-1 bytes to search LOOK: SUB AX,BX ;subtract initial offset JB SEARCH_NOT_FOUND ;offset < search size? CMP AX,DI ;compare to string size JB SEARCH_NOT_FOUND ;less than search size? MOV DX,AX ;dx gets search size MOV CL,4 ; SHR DX,CL ;number of segments to search SUB SEARCH_PARAS,DX ;decrease the amount to search ;si = search string di = size ;es:bx=start addr CALL SEARCH ;ax=bytes to search JZ SEARCH_FOUND ;if zero flag, string is found ADD AX,1 ;next character after fail MOV BX,AX ;into es:bx JNC NOWR ;if offset rolls over MOV AX,ES ;add 64k ADD AX,1000H ;to the MOV ES,AX ;offset NOWR: CALL NORMALIZE ;change ES:BX so that ; 10h > BX >= 0 JMP LOOK_AGAIN SEARCH_NOT_FOUND: XOR AX,AX ;start over MOV ES,AX CMP AL,1 ;clear zero flag SEARCH_FOUND: MOV START_SEGMENT,ES ;set address of found string MOV START_OFFSET,AX RET SEARCH_MEM ENDP ;----------------------------------------------------------------- ; END_MINUS_START ; using START_OFFSET, START_SEGMENT, END_OFFSET, and END_SEGMENT, ; return SEARCH_BYTES, SEARCH_PARAS, and normalized pointer to ; starting address in ES:BX ;----------------------------------------------------------------- END_MINUS_START PROC NEAR LES BX,DWORD PTR START_OFFSET ;start addr in ES:BX CALL NORMALIZE ;change es:bx so 10h > bx >=0 MOV AX,ES ;save normalized result MOV CX,BX ;for later use LES BX,DWORD PTR END_OFFSET ;get end address CALL NORMALIZE ;change es:bx so 10h > bx >=0 MOV DX,ES ;get end segment SUB DX,AX ;calculate paragraphs to search MOV SEARCH_PARAS,DX ;and save MOV SEARCH_BYTES,BX ;# bytes after final paragraph MOV ES,AX ;set es:bx to MOV BX,CX ; start address RET ;that's all END_MINUS_START ENDP ;----------------------------------------------------------------- ; NORMALIZE ; make 20 bit pointer in es:bx from segment:offset in es:bx, ; i.e. adjust ES:BX to point to same absolute address, but with ; 10h > BX >= 0 ;----------------------------------------------------------------- NORMALIZE PROC NEAR PUSH AX ;save registers PUSH CX PUSH DX MOV AX,BX ;get the offset MOV CL,4 ;make into SHR AX,CL ;number of paragraphs MOV DX,ES ;get segment ADD DX,AX ;add in number of paragraphs MOV ES,DX ;back into segment SHL AX,CL ;calc offset into segment SUB BX,AX ; (BX mod 16) POP DX ;restore registers POP CX POP AX RET NORMALIZE ENDP ;----------------------------------------------------------------- ; SEARCH ; si = search string di = string size es:bx = pointer to buffer to search ; ax = number of bytes in buffer to search. If found, zero flag set, and ; es:bx points to found string. If not found, zero flag cleared, and es:bx ; points to last first byte checked. ;----------------------------------------------------------------- SEARCH PROC NEAR PUSH BX PUSH DI PUSH SI XCHG BX,DI ;bx=string size, es:di=ptr to data area MOV CX,AX ;# chars in segment to search BYTE_ADD: LODSB ;char for first part of search NEXT_SRCH: REPNZ SCASB ;is first char in string in buffer JNZ NOT_FOUND ;if not, no match PUSH DI ;save against cmpsb PUSH SI PUSH CX LEA CX,[BX-1] ;# chars in string - 1 (CX=BX-1) JCXZ ONE_CHAR ;if one char search, we have found it REP CMPSB ;otherwise compare rest of string ONE_CHAR: POP CX ;restore for next cmpsb POP SI POP DI JNZ NEXT_SRCH ;if zr = 0 then string not found NOT_FOUND: LEA AX,[DI-1] ;ES:AX=ptr to last first character found ; (AX=DI-1) POP SI ;restore registers POP DI POP BX RET SEARCH ENDP ;------------------------------------------------------------------ ; UNINSTALL - removes resident program from memory if possible. if not, ; toggles the disable flag ;------------------------------------------------------------------ UNINSTALL PROC NEAR CALL HOOKED_VECTORS_SAME? ;if all vectors still hooked JZ UNINSTALL_OK ;go ahead and uninstall MOV ES,INSTALLED_SEGMENT ;else, change the disable flag NOT ES:DISABLE ;in the installed program MOV DX,OFFSET ENABLED ;get the message corresponding CMP ES:DISABLE,-1 ;to the action that causes JNZ ITS_DISABLED ; MOV DX,OFFSET DISABLED ; ITS_DISABLED: ; MOV AH,9 ;and display that message INT 21H JMP SHORT UNINSTALL_EXIT ;all done here. UNINSTALL_OK: MOV ES,INSTALLED_SEGMENT ;get resident prog's psp NOT ES:WORD PTR START ;mark resident program inactive MOV DX,ES:WORD PTR ADDR_INT9H ;restore int 9 vector MOV DS,ES:WORD PTR ADDR_INT9H+2 MOV AH,25H MOV AL,9 INT 21H MOV DX,ES:WORD PTR ADDR_INT10H ;restore int 10h vector MOV DS,ES:WORD PTR ADDR_INT10H+2 MOV AH,25H MOV AL,10H INT 21H PUSH ES MOV ES,ES:[2CH] ;get segment of environment MOV AH,49H ;belonging to resident program INT 21H ;free it POP ES MOV AH,49H ;free memory block of program INT 21H PUSH CS POP DS ;get back our data segment MOV DX,OFFSET UNINSTALLED ;display message MOV AH,9 INT 21H UNINSTALL_EXIT: RET UNINSTALL ENDP ;------------------------------------------------------------------ ; HOOKED_VECTORS_SAME? ; determine if vectors have changed since program was installed. ; if changed, zero flag cleared; if not changed, zero flag set. ;------------------------------------------------------------------ HOOKED_VECTORS_SAME? PROC NEAR MOV CX,INSTALLED_SEGMENT ;get executing segment XOR AX,AX ;interrupt table segment MOV ES,AX ;into the extra segment CMP CX,ES:[10H*4+2] ;see if int 10h points at us JNZ VECTOR_CHANGED CMP CX,ES:[9*4+2] ;see if int 9 points at us VECTOR_CHANGED: RET HOOKED_VECTORS_SAME? ENDP ;---------------------------------------------------------------------- ; INSTALL - links vectors 9h and 10h to our code ;---------------------------------------------------------------------- INSTALL PROC NEAR MOV CL,9 ;link vector 9 MOV SI,OFFSET ADDR_INT9H MOV DI,OFFSET INT9H CALL INSTALL_VECTOR MOV CL,10H ;link vector 10h MOV SI,OFFSET ADDR_INT10H MOV DI,OFFSET INT10H CALL INSTALL_VECTOR RET INSTALL ENDP ;---------------------------------------------------------------------- ; INSTALL_VECTOR - generic vector-linking routine ;---------------------------------------------------------------------- INSTALL_VECTOR PROC NEAR MOV AL,CL ;get vector number MOV AH,35H ;get interrupt vector INT 21H ; MOV [SI],BX ;save interrupt vector MOV [SI+2],ES ; MOV DX,DI ;get replacement address MOV AH,25H ;set vector address MOV AL,CL ;for vector INT 21H RET INSTALL_VECTOR ENDP _TEXT ENDS END START